Springer Nature is making SARS-CoV-2 and COVID-19 research free View research | View latest news | Sign up for updates

Unilateral displacement of lower limb evokes bilateral EMG responses in leg and foot muscles in standing humans

  • 106 Accesses

  • 33 Citations


During upright stance, foot dorsiflexion induced by the movement of a supporting platform elicits a short-(SLR) and a medium-latency response (MLR) in both the soleus and the flexor digitorum brevis muscles; foot plantarflexion elicits a MLR in the tibialis anterior. The SLR is the counterpart of the stretch reflex, but no general agreement exists about the origin of the MLR, though recent results suggest that it is transmitted through group II afferent fibres. Animal studies have shown that group II fibres impinge on interneurones projecting contralaterally as well as ipsilaterally, whereas group I fibres impinge on interneurones which project mainly ipsilaterally. Therefore, we compared the changes in amplitude and latency of the SLRs and MLRs in the right and left limb during postural perturbations induced while subjects maintained both feet on the platform (both-on condition) or while they maintained only one foot on the platform and the other on firm ground (one-on condition). Under the both-on condition, the pattern of EMG responses described above occurred bilaterally. Under the one-on condition, both SLRs and MLRs occurred in the displaced leg. However, whereas the SLRs did not change in amplitude compared with the both-on condition, the MLRs decreased in amplitude to about 50%. MLRs were also present in the non-displaced leg. They were not preceded by any SLR but showed a further decrease in size with respect to the corresponding responses in the perturbed leg. Latency of the MLRs of the perturbed leg increased by about 5 ms passing from the both-on to the one-on condition. In the latter condition, a further increase of 5 ms was observed in the nonperturbed leg with respect to the displaced one. The occurrence of the MLRs but not of the SLRs in the contralateral non-displaced leg is in keeping with the notion that crossed neural pathways fed by spindle group II afferent fibres subserve the MLRs. The changes in latency of the MLRs under the one-on condition compared with both-on give a cue about the synaptic delays along the neural circuit and the time taken by the afferent impulses to cross the spinal cord.

This is a preview of subscription content, log in to check access.


  1. Aniss AM, Gandevia SC, Burke D (1992) Reflex responses in active muscles elicited by stimulation of low-threshold afferents from the human foot. J Neurophysiol 67:1375–1384

  2. Bajwa S, Edgley SA, Harrison PJ (1992) Crossed actions on group II-activated interneurones in the midlumbar segments of the cat spinal cord. J Physiol (Lond) 455:205–217

  3. Berardelli A, Hallett M, Kaufman C, Fine E, Berenberg W, Simon SR (1982) Stretch reflexes of triceps surae in normal man. J Neurol Neurosurg Psychiatry 45:513–525

  4. Berger W, Dietz V, Quintern J (1984) Corrective reactions to stumbling in man: neuronal co-ordination of bilateral leg muscle activity during gait. J Physiol (Lond) 357:109–125

  5. Bras H, Cavallari P, Jankowska E, McCrea D (1989) Comparison of effects of monoamines on transmission in spinal pathways from group I and group II muscle afferents in the cat. Exp Brain Res 76:27–37

  6. Corna S, Grasso M, Nardone A, Schieppati M (1995) Selective depression of medium-latency leg and foot muscle responses to stretch by an α2-agonist in humans. J Physiol (Lond) 484:803–809

  7. Delwaide PJ, Crenna P (1983) Exteroceptive influences on lower limb motoneurons in man: spinal and supraspinal contributions. In: Desmedt JE (ed) Motor control mechanisms in health and disease. Raven, New York, pp 797–807

  8. Diener H-C, Dichgans J, Guschlbauer B, Mau H (1984) The significance of proprioception on postural stabilization as assessed by ischemia. Brain Res 296:103–109

  9. Dietz V (1992) Human neuronal control of automatic functional movements: interaction between central programs and afferent input. Physiol Rev 72:33–69

  10. Dietz V, Berger G (1982) Spinal coordination of bilateral leg muscle activity during balancing. Exp Brain Res 47:172–176

  11. Dietz V, Berger W (1984) Interlimb coordination of posture in patients with spastic paresis. Impaired function of spinal reflexes. Brain 107:965–978

  12. Dietz V, Quintern J, Berger W (1985) Afferent control of human stance and gait: evidence for blocking of group I afferents during gait. Exp Brain Res 61:153–163

  13. Dietz V, Horstmann GA, Berger W (1989) Interlimb coordination of leg-muscle activation during perturbation of stance in humans. J Neurophysiol 62:680–693

  14. Duysens J, Tax T (1994) Interlimb reflexes during gait in cat and human. In: Interlimb coordination: neural, dynamical and cognitive constraints. Academic, New York, pp 97–126

  15. Gibbs J, Harrison ML, Stephens JA (1995) Cutaneomuscular reflexes recorded from the lower limb in man during different tasks. J Physiol (Lond) 487:237–242

  16. Fu TC, Schomburg ED (1974) Electrophysiological investigation of the projection of secondary muscle spindle afferents in the cat spinal cord. Acta Physiol Scand 91:314–329

  17. Harrison PJ, Zytnicki D (1984) Crossed actions of group I muscle afferents in the cat. J Physiol (Lond) 356:263–273

  18. Harrison PJ, Evans P, Greenslade S, McCabe R (1994) Crossed proprioceptive reflexes in the human leg. J Physiol (Lond) 479:28P

  19. Jankowska E (1992) Interneuronal relay in spinal pathway from proprioceptors. Progr Neurobiol 38:335–378

  20. Kukulka CG (1994) The reflex effects of nonnoxious sural nerve stimulation on human triceps surae motor neurons. J Neurophysiol 71:1897–1906

  21. Müller K, Hömberg V, Coppenrath P, Lenard HG (1991) Maturation of lower extremity EMG responses to postural perturbations: relationship of response latencies to development of fastest central and peripheral efferents. Exp Brain Res 84:444–452

  22. Munson JB, Fleshman JW, Sypert GW (1980) Properties of single fiber spindle group II EPSPs in triceps surae motoneurons. J Neurophysiol 44:713–725

  23. Nardone A, Corrà T, Schieppati M (1990a) Different activations of the soleus and gastrocnemii muscles in response to various types of stance perturbations in man. Exp Brain Res 80:323–332

  24. Nardone A, Giordano A, Corrà T, Schieppati M (1990b) Responses of leg muscles in humans displaced while standing. Effects of types of perturbation and of postural set. Brain 113:65–84

  25. Schieppati M (1987) The Hoffmann reflex: a means of assessing spinal reflex excitability and its descending control in man. Progr Neurobiol 28:345–376

  26. Schieppati M, Crenna P (1984) Natural cutaneous stimulation induces late and long-lasting facilitation of extensor motoneurons in the cat. Brain Res 293:259–267

  27. Schieppati M, Nardone A (1991) Free and supported stance in Parkinson's disease: the effects of posture and “postural set” on leg muscle responses to perturbation, and its relation to the severity of the disease. Brain 114:1227–1244

  28. Schieppati M, Nardone A (1995) Time-course of “set”-related changes in muscle responses to stance perturbation in humans. J Physiol (Lond) 487:787–796

  29. Schieppati M, Nardone A, Corna S (1995a) Do secondary spindle afferents play a role in the late response to stretch of leg muscles in humans? In: Taylor A, Gladden MH, Durbaba R (eds) Alpha and gamma motor systems. Plenum, London, pp 529–532

  30. Schieppati M, Nardone A, Siliotto R, Grasso M (1995b) Early and late stretch response of human foot muscles induced by perturbation of stance: Exp Brain Res 105:411–422

  31. Shimamura M, Mori S, Matsushima S, Fujimori B (1964) On the spino-bulbo-spinal reflex in dogs, monkeys and man. Jpn J Physiol 14:411–421

  32. Siliotto R, Grasso M, Nardone A, Schieppati M (1996) Contribution of foot muscle responses to postural stabilization. In: Stuart DG, Gantchev GN, Gurfinkel VS, Wiesendanger M (eds) Motor control VII. Motor Control Press, Tucson, in press

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Corna, S., Galante, M., Grasso, M. et al. Unilateral displacement of lower limb evokes bilateral EMG responses in leg and foot muscles in standing humans. Exp Brain Res 109, 83–91 (1996). https://doi.org/10.1007/BF00228629

Download citation

Key words

  • Posture
  • Spindle group II afferents
  • Crossed pathways
  • EMG
  • Human